Previously, two types of brake control arrangements were shown and described in Japanese Patent Application Nos. 57-172181 and 58-93176. From now on, the two arrangements will be referred to as the first brake control arrangement and a second brake control arrangement. These two ordinary brake control arrangements are depicted in FIGS. 2 through 7. Referring now to FIG. 2, there is shown an electropneumatic braking system which may be defined as the first control method. The powered motor car (M car) and nonpowered trailer car (T car) are each equipped with a fluid brake system 17m, 17t, respectively, each of which consists of an electricfluid pressure change valve EP, a relay valve RV, and a brake cylinder BC. A compound brake power command signal F is produced by a compound brake power command signal controller 2 which may be referred to as a command controller. The command signal F is transferred to the electric brake power command controller 3, the positive input of a first-second operator of summing network 72a, and the T car setter 9 which is set by a suitable weight-response device carried by the T car. The electric brake power command controller 3 has limited capacity. In other words, when the compound brake power command signal F is less than the maximum adhesion brake power equivalent signal H, the electric brake power command signal E, which is the output of the electric brake power command 3, is equal to the compound brake power command signal F, (E=F). When the compound brake command signal F is greater than the maximum adhesion brake power equivalent signal H, the electric brake power command signal E is equal to the maximum adhesion brake power equivalent signal H, (E=H). Depending on this electric brake power command signal E, the electric brake system 4, such as, regenerative or dynamic, is rendered functional so that the elecelectric brake power equivalent signal G which is required for the real electric brake power is transferred to the negative input of a first operator 71. The first operator or summing network 71 subtracts the electric brake power equivalent signal G from the electric brake power command signal E and transfers the result (E-G) to the T car setter 6t as well as to the M car setter 6m. The T car setter 6t produces an output which is (E-G).T/(M+T). This T car allocation is conveyed to the positive input of the second operator 72b. The M car setter 6m produces an output which is (E-G).M/(M+T). This M car allocation is conveyed to the positive input of the fifth operator 75. Here, M stands for the weight of the M car (motor car) and T stands for the weight of the T car (trailer car) where generally (M&gt;T).
It will be appreciated that the first-second operator 72a subtracts the electric brake power command signal E from the compound brake power command signal F and transfers the result (F-E) to the positive input of the second-second operator 72b. The second-second operator 72b adds the two inputs (F-E) and (E-G).T/(M+T) and transfers the result (F-E)+(E-G).T/(M+T) to the positive input of the third summing operator 73 and to the positive input of the fourth operator 74. The third operator 73 subtracts the output of the T car setter, namely F.T/(M+T), from the input (F-E)+(E-G).T/(M+T) and transfers the result (F-E)+(E-G).T/(M+T)-F.T/(M+T) to a diode 76. The diode 76 transfers the output of the third operator 73 to the negative input of the fourth operator 74 and to the positive input of the fifth operator 75 when the output of the third operator 73 is positive. When the output of the third operator 73 is less than 0, it conveys a 0 to the fourth and fifth operators. The fourth operator 74 subtracts the output of diode 76 from the output of the second operator 72, and transfers the result as a fluid brake power command signal to the T car fluid brake system 17t via the T car amplifier 10t. The fifth operator 75 adds the output of the M car setter 6m, namely (E-G).M/(M+T), and the output of diode 76 and then transfers the result as the fluid brake power command signal to the M car fluid brake system 17m via the M car amplifier 10m. The above-described T car fluid brake power command signal and M car fluid brake power command signal can be considered to be the fluid brake power of the T car and the M car.
Also, the above-described electric brake power equivalent signal G can be considered to be the electric brake power, and the synthesized brake power of the M car is the sum of the fluid brake power and the electric brake power of the M car. Therefore, the following can be assumed:
(I)
When F&lt;H then, PA1 T car fluid brake power=(F-G).T/(M+T) PA1 M car fluid brake power=(-G).M/(M+T) PA1 M car synthesized brake power=(F-G).M/(M+T)+G PA1 When F.gtoreq.H then, PA1 When F&lt;H then, PA1 Bt=Bm=(F-G)/(M+T) PA1 BM=(F-G)/(M+T)=G/M PA1 When F.gtoreq.H and PA1 When G.gtoreq.(F-H).M/T then, PA1 When G&gt;F.M/(M+T) then, PA1 T car fluid brake power=(F-G) PA1 M car fluid brake power=0 PA1 M car synthesized brake power=G PA1 When G.ltoreq.F.M/(M+T) then, PA1 T car fluid brake power=F.M/(M+T) PA1 M car fluid brake power=F.M/(M+T)-G PA1 M car synthesized brake power=F.M/(M+T) PA1 Then, the fluid brake deceleration rate Bt of the T car, the fluid brake deceleration rate Bm of the M car, and the synthesized deceleration rate BM of the M car are as follows: PA1 When G&gt;F.M/(M+T) then, PA1 Bt=(F-G)/T PA1 Bm=0 PA1 BM=G/M PA1 When G.ltoreq.F.M/(M+T) then, PA1 Bt=F/(M+T) PA1 Bm=F/(M+T)-G/M PA1 BM=F/(M+T)
(II)
(a)
T car fluid brake power=(H-G).T/(M+T)+(F-H) PA2 M car fluid brake power=(H-G).M/(M+T) PA2 M car synthesized brake power=(H-G).M/(M+T)+G PA2 When B-(F-H).M/T then, PA2 T car fluid brake power=F.T/(M+T) PA2 M car fluid brake power=F.M/(M+T)-G PA2 M car synthesized brake power=F.M/(M+T) PA2 Bt=(H-G)/(M+T)+(F-H)/T PA2 Bm=(H-G)/(M+T) PA2 BM=(H-G)/(M+T)+G/M PA2 When G&lt;(F-H).M/T then, PA2 Bt=F/(M+T) PA2 Bm=F/(M+T)-G/M PA2 BM=F/(M+T)
(b)
The deceleration rate is the brake power divided by the weight. Therefore, the fluid brake deceleration rate of the T car, namely Bt; and the fluid brake deceleration rate of the M car, namely Bm; and the synthesized deceleration rate of the M car, namely BM; are as follows:
(I)
(II)
(a)
(b)
The relationship between these deceleration rates Bt, Bm, BM and the electric brake ratio (G/E) is shown in FIG. 3 and FIG. 4. It will be seen that FIG. 3 shows the case in which (F&lt;H), in other words, the compound brake power command signal F is less than the maximum adhesion brake power equivalent signal H. The fluid brake deceleration rate Bm of the M car and the fluid brake deceleration rate Bt of the T car increases from 0 to F/(M+T) with a decrease in the electric brake ratio from 100%. The synthesized deceleration rate BM of the M car decreases from (F/M) to (F/(M+T)) with a decrease in the electric brake ratio from 100%. It will be seen that FIG. 4 shows the case in which (F.gtoreq.H), in other words, the compound brake power command signal F is larger than the maximum adhesion brake power equivalent signal H. The fluid brake deceleration rate Bt of the T car is (F-H)/T when the electric brake ratio is 100%, and Bt increases with a decrease in the electric brake ratio. In the area where G&lt;(F-H).M/T, Bt is constant, and it is equal to F/(M+T). The fluid brake deceleration rate Bm of the M car increases from 0 with a decrease in the electric brake ratio from 100%, and the increase is larger in the area where G&lt;(F-H).M/T than in the area where G.gtoreq.(F-H).M/T, and it reaches F/(M+T) when the electric brake ratio is 0%.
The synthesized deceleration rate BM of the M car is (H/M) when the electric brake ratio is 100%, and decreases with a decrease in the electric brake ratio, and it is constant F/(M+T) in the area where G&lt;(F-H).M/T.
Referring now to FIG. 5, there is shown another system which uses a second brake control method. The parts which are the same as in FIG. 2 are numbered by the same reference characters and a detailed explanation has been omitted for the sake of convenience.
The compound brake power command signal command controller 2, electric brake power command controller 3, electric brake system 4, T car amplifier 10t, M car amplifier 10m, T car fluid brake system 17t, and the M car fluid brake system 17m are all the same as those described in FIG. 2. The T car setter 6t conveys F.T/(M.T), which is the fraction of the compound brake power command signal F that is allocated to the T car to the positive input of a first operator 81.
The M car setter 6m conveys F.M/(M.T), which is the fraction of the compound brake power command signal F that is allocated to the M car to the negative input of a second operator 82 and to the positive input of a third operator 83. The second operator 82 subtracts F.M/(M+T), which is the output of the M car setter 6m that was transferred into the positive input of the second operator 82 and it then transfers the results G-F.M/(M+T) to a first diode 84.
The first diode 84 outputs this unchanged when the output of the second operator 82 is positive. When the output of the second operator 82 is less than 0, it outputs 0 and transfers it to the negative input of the first operator 81.
The first operator 81 subtracts the output of the first diode 84 from F.T/(M+T), which is the output of the T car setter 6t and transfers the result to the T car fluid brake system 17t as the fluid brake power command signal of the T car via the T car amplifier 10t.
The third operator 83 subtracts the electric brake power equivalent signal G, which is transferred into the negative input of the third operator from F.M/(M+T) which is the output of the M car setter 6m, and it is transferred into the positive input of the third operator 83, and the result F.M/(M+T) is transferred to the second diode 85.
The second diode 85 outputs the signal unchanged when the output of the third operator 83 is positive. When the output of the third operator 83 is less than 0, it outputs 0 and transfers it to the M car fluid brake system 17m as the fluid brake power command signal of the M car via the M car amplifier 10m. Just like the first-known method, the fluid brake power of the T car, the fluid brake power of the M car, and the synthesized brake power of the M car are designed as follows:
(I)
(II)
(I)
(II)
The relationships between the deceleration rate Bt, Bm, BM and the electric brake ratio (G/E) are shown in FIGS. 6 and 7. It will be appreciated that FIG. 6 shows the case where (F&lt;H), in other words, when the compound brake power command signal F is less than the maximum adhesion brake power equivalent signal H. The fluid brake deceleration rate Bt of the T car is 0 when the electric brake ratio is 100%, and it rises with a decrease in the electric brake ratio. It is constant F/(M+T) in the area where G.ltoreq.F.M/(M+T). The fluid brake deceleration rate Bm of the M car is 0, while the electric brake ratio ranges from 100% to the point where G=F.M/(M+T). When G.ltoreq.F.M/(M+T), M rises with a decrease in the electric brake ratio and it becomes F/(M+T) when the electric brake ratio is 0%. The synthesized deceleration rate BM of the M car is (F.M) when the electric brake ratio is 100%, and it falls with a decrease in the electric brake ratio. It becomes F/(M+T) when G.ltoreq.F.M/(M+T). It will be seen that FIG. 7 shows the case when (F.gtoreq.H), in other words, when the compound brake power command signal F is larger than the maximum adhesion brake power equivalent signal H. The fluid brake deceleration rate Bt of the T car is F-H/T when the electric brake ratio is 100%, and it rises with a decrease in the electric brake ratio. It becomes constant F/(M+T) when G.gtoreq.F.M/(M+T). The fluid brake deceleration rate Bm of the M car is 0 in the area where the electric brake ratio is from 100% to G=F.M/(M+T). In the area where G.gtoreq.F.M/(M+T) it rises with a decrease in the electric brake ratio, and it becomes F/(M+T) when the electric brake ratio is 0%. The synthesized deceleration rate BM of the M car is (H/M) when the electric brake ratio is 100 %, and it falls with a decrease in the electric brake ratio, and it becomes constant F/(M+T) in the area where G.gtoreq.F.M/(M+T).